Techniques for reducing feedback information

Abstract

This disclosure provides systems, devices, apparatus, and methods, including computer programs encoded on storage media, for techniques for reducing feedback information in an extremely high throughput (EHT) wireless local area network (WLAN). A receiving device (beamformee), such as a station (STA), may receive a sounding signal from a transmitting device (beamformer), such as an access point (AP), and transmit channel feedback. The receiving device may transmit the channel feedback as part of a reduced compressed beamforming feedback (CBF) operation that includes determining a first set of channel characteristics. The receiving device may select a subset of the first set of channel characteristics and determine a set of differential characteristics based on the subset. The transmitting device may then transmit the sets of characteristics as reduced CBF to the transmitting device. The transmitting device may determine a channel estimation for beamformed signaling based on the reduced CBF.

What is claimed is: 
     
       1. A method for wireless communication at a station (STA), comprising:
 receiving, from an access point (AP), a sounding signal comprising one or more spatial streams transmitted over an operating bandwidth; 
 determining a first set of channel characteristics of the operating bandwidth for an average channel of the operating bandwidth based at least in part on receiving the sounding signal, the first set of channel characteristics comprising a first dimensionality and a second dimensionality to; 
 reducing a value of the first dimensionality of the first set of channel characteristics for the average channel of the operating bandwidth based at least in part on a feedback reduction parameter corresponding to an averaging bandwidth for calculating the average channel, the averaging bandwidth being based at least in part on a signal strength threshold corresponding to a localized average channel of the average channel calculated for a sub-bandwidth of the operating bandwidth, wherein the sounding signal comprises the feedback reduction parameter, the feedback reduction parameter being determined in a bi-directional joint procedure between the STA and the AP; 
 determining a second set of channel characteristics for the averaging bandwidth based at least in part on reducing the first set of channel characteristics; and 
 transmitting, to the AP, the second set of channel characteristics, 
 wherein:
 determining the first set of channel characteristics comprises: 
 determining the average channel of the operating bandwidth based at least in part on the averaging bandwidth; and 
 determining the second set of channel characteristics comprises: 
 determining a set of differential characteristics between the reduced first set of channel characteristics corresponding to the averaging bandwidth for calculating the average channel and characteristics of a second channel of the operating bandwidth. 
 
 
     
     
       2. The method of  claim 1 , wherein transmitting the second set of channel characteristics and the feedback reduction parameter further comprises transmitting a multiple input multiple output (MIMO) control field formatted to include one or more indications of the feedback reduction parameter associated with the second set of channel characteristics. 
     
     
       3. The method of  claim 1 , further comprising determining a numerical quantity of feedback bits associated with the set of differential characteristics, wherein the numerical quantity of feedback bits is based at least in part on a numerical quantity of generated angles for the set of differential characteristics. 
     
     
       4. The method of  claim 1 , further comprising configuring a compressed beamforming report field to include the reduced first set of channel characteristics and the set of differential characteristics, wherein transmitting the second set of channel characteristics comprises transmitting an action frame containing the reduced first set of channel characteristics and the set of differential characteristics as feedback in the compressed beamforming report field. 
     
     
       5. The method of  claim 1 , further comprising determining the average channel over an extended bandwidth that exceeds the averaging bandwidth. 
     
     
       6. The method of  claim 1 , wherein the feedback reduction parameter is based at least in part on one or more of: a performance loss, a component of a transmit correlation matrix, the operating bandwidth, or an averaging bandwidth of the operating bandwidth, wherein the averaging bandwidth of the operating bandwidth comprises a reduced portion of the operating bandwidth. 
     
     
       7. The method of  claim 1 , further comprising determining a numerical quantity of feedback bits associated with the second set of channel characteristics, wherein the numerical quantity of feedback bits is based at least in part a numerical quantity of generated angles for the second set of channel characteristics. 
     
     
       8. The method of  claim 1 , further comprising transmitting a capability bit to indicate support at the STA for reduced compressed beamforming feedback, wherein receiving the sounding signal is based at least in part on transmitting the capability bit. 
     
     
       9. The method of  claim 1 , wherein the second set of channel characteristics comprises compressed beamforming feedback information. 
     
     
       10. The method of  claim 1 , wherein the operating bandwidth comprises a first bandwidth of at least 320 MHz or a second bandwidth comprising a first 160 MHz portion and a second non-adjacent 160 MHz portion. 
     
     
       11. The method of  claim 1 , wherein the STA supports multi-antenna operations over a plurality of spatial streams. 
     
     
       12. The method of  claim 2 , further comprising configuring the MIMO control field to include at least one bit for indicating that a reduced compressed beamforming feedback operation is associated with the second set of channel characteristics, the at least one bit including one or more reserved bits of the MIMO control field. 
     
     
       13. The method of  claim 2 , further comprising configuring one or more index subfields of the MIMO control field to indicate the feedback reduction parameter, or the averaging bandwidth for the second set of channel characteristics, or both, wherein the feedback reduction parameter comprises a reduction value, the averaging bandwidth, or both. 
     
     
       14. The method of  claim 2 , further comprising extending one or more subfields of the MIMO control field, the one or more subfields indicating a capability for support for a reduced compressed beamforming feedback operation over the operating bandwidth, wherein the feedback reduction parameter comprises information indicating the capability for support for the reduced compressed beamforming feedback operation over the operating bandwidth. 
     
     
       15. The method of  claim 7 , wherein the second set of channel characteristics are determined as part of a single user sounding procedure or as part of a multi-user sounding procedure. 
     
     
       16. A method for wireless communication at an access point (AP), comprising:
 determining a feedback reduction parameter for a channel sounding procedure, wherein the feedback reduction parameter is for reducing a value of a first dimensionality of a set of channel characteristics for an average channel; 
 transmitting, to a station (STA), a sounding signal comprising one or more spatial streams transmitted over an operating bandwidth, wherein the feedback reduction parameter corresponds to an averaging bandwidth for calculating the average channel, the averaging bandwidth being based at least in part on a signal strength threshold corresponding to a localized average channel of the average channel calculated for a sub-bandwidth of the operating bandwidth, wherein the sounding signal comprises the feedback reduction parameter, the feedback reduction parameter being determined in a bi-directional joint procedure between the STA and the AP; and 
 receiving the set of channel characteristics and the feedback reduction parameter from the STA based at least in part on transmitting the sounding signal, the set of channel characteristics having a reduced first dimensionality or a reduced second dimensionality, or both according to the feedback reduction parameter, 
 wherein the feedback reduction parameter is based at least in part on the averaging bandwidth for calculating the average channel. 
 
     
     
       17. The method of  claim 16 , further comprising:
 receiving a set of differential characteristics from the STA, wherein the set of differential characteristics are received with the set of channel characteristics; 
 determining a channel on one or more sub carriers of the operating bandwidth based at least in part on the set of channel characteristics and the set of differential characteristics; and 
 transmitting a beamformed signal over the channel to the STA based at least in part on the determining. 
 
     
     
       18. The method of  claim 16 , further comprising:
 transmitting a frame including one or more indications of the feedback reduction parameter associated with the set of channel characteristics; and 
 configuring at least one bit in a field of the frame to indicate a reduced compressed beamforming feedback operation. 
 
     
     
       19. The method of  claim 16 , wherein the set of channel characteristics are received as part of a single user sounding procedure or as part of a multi-user sounding procedure. 
     
     
       20. The method of  claim 16 , wherein the feedback reduction parameter is based at least in part on one or more of: a performance loss, a component of a transmit correlation matrix, or the operating bandwidth. 
     
     
       21. The method of  claim 16 , further comprising transmitting a capability bit to indicate support at the AP for reduced compressed beamforming feedback, wherein transmitting the sounding signal is based at least in part on transmitting the capability bit. 
     
     
       22. The method of  claim 18 , further comprising configuring one or more index subfields of the frame to indicate the feedback reduction parameter, or the averaging bandwidth for the set of channel characteristics, or both. 
     
     
       23. An apparatus for wireless communication at a station (STA), comprising:
 one or more processors; and 
 one or more memories in electronic communication with the one or more processors and storing one or more instructions, 
 the one or more instructions executable by the one or more processors to cause the apparatus to:
 receive, from an access point (AP), a sounding signal comprising one or more spatial streams transmitted over an operating bandwidth; 
 determine a first set of channel characteristics of the operating bandwidth for an average channel of the operating bandwidth based at least in part on receiving the sounding signal, the first set of channel characteristics comprising a first dimensionality and a second dimensionality to; 
 reduce a value of the first dimensionality of the first set of channel characteristics for the average channel of the operating bandwidth based at least in part on a feedback reduction parameter corresponding to an averaging bandwidth for calculating the average channel, the averaging bandwidth being based at least in part on a signal strength threshold corresponding to a localized average channel of the average channel calculated for a sub-bandwidth of the operating bandwidth, wherein the sounding signal comprises the feedback reduction parameter, the feedback reduction parameter being determined in a bi-directional joint procedure between the STA and the AP; 
 determine a second set of channel characteristics for the averaging bandwidth based at least in part on reducing the first set of channel characteristics; and 
 transmit, to the AP, the second set of channel characteristics, 
 wherein: 
 determining the first set of channel characteristics comprises: 
 determining the average channel of the operating bandwidth based at least in part on the averaging bandwidth; and 
 determining the second set of channel characteristics comprises: 
 determining a set of differential characteristics between the reduced first set of channel characteristics corresponding to the averaging bandwidth for calculating the average channel and characteristics of a second channel of the operating bandwidth. 
 
 
     
     
       24. The apparatus of  claim 23 , wherein the one or more instructions to transmit the second set of channel characteristics and the feedback reduction parameter further are executable by the one or more processors to cause the apparatus to transmit a multiple input multiple output (MIMO) control field formatted to include one or more indications of the feedback reduction parameter associated with the second set of channel characteristics. 
     
     
       25. The apparatus of  claim 24 , wherein the one or more instructions are further executable by the one or more processors to cause the apparatus to configure the MIMO control field to include at least one bit for indicating that a reduced compressed beamforming feedback operation is associated with the second set of channel characteristics, the at least one bit including one or more reserved bits of the MIMO control field. 
     
     
       26. The apparatus of  claim 24 , wherein the one or more instructions are further executable by the one or more processors to cause the apparatus to configure one or more index subfields of the MIMO control field to indicate the feedback reduction parameter, or the averaging bandwidth for the second set of channel characteristics, or both, wherein the feedback reduction parameter comprises a reduction value, the averaging bandwidth, or both. 
     
     
       27. The apparatus of  claim 24 , wherein the one or more instructions are further executable by the one or more processors to cause the apparatus to extend one or more subfields of the MIMO control field, the one or more subfields indicating a capability for support for a reduced compressed beamforming feedback operation over the operating bandwidth, wherein the feedback reduction parameter comprises information indicating the capability for support for the reduced compressed beamforming feedback operation over the operating bandwidth. 
     
     
       28. An apparatus for wireless communication at an access point (AP), comprising:
 one or more processors; and 
 one or more memories in electronic communication with the one or more processors and storing one or more instructions, 
 the one or more instructions executable by the one or more processors to cause the apparatus to:
 determine a feedback reduction parameter for a channel sounding procedure, wherein the feedback reduction parameter is for reducing a value of a first dimensionality of a set of channel characteristics for an average channel; 
 transmit, to a station (STA), a sounding signal comprising one or more spatial streams transmitted over an operating bandwidth, wherein the feedback reduction parameter corresponds to an averaging bandwidth for calculating the average channel; and 
 receive the set of channel characteristics and the feedback reduction parameter from the STA based at least in part on transmitting the sounding signal, the set of channel characteristics having a reduced first dimensionality or a reduced second dimensionality, or both according to the feedback reduction parameter, the averaging bandwidth being based at least in part on a signal strength threshold corresponding to a localized average channel of the average channel calculated for a sub-bandwidth of the operating bandwidth, wherein the sounding signal comprises the feedback reduction parameter, the feedback reduction parameter being determined in a bi-directional joint procedure between the STA and the AP, 
 wherein the feedback reduction parameter is based at least in part on the averaging bandwidth for calculating the average channel. 
 
 
     
     
       29. The apparatus of  claim 28 , wherein the one or more instructions are further executable by the one or more processors to cause the apparatus to:
 receive a set of differential characteristics from the STA, wherein the set of differential characteristics are received with the set of channel characteristics; 
 determine a channel on one or more sub carriers of the operating bandwidth based at least in part on the set of channel characteristics and the set of differential characteristics; and
 transmit a beamformed signal over the channel to the STA based at least in part on the determining.